@import url('https://fonts.googleapis.com/css?family=Roboto+Mono&display=swap');

* {
    box-sizing: border-box;
}

body {
    overflow: hidden;
    /* 水平居中 */
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0;
    height: 100vh;
    color: #fff;
    font-family: 'Roboto Mono', sans-serif;
    /* 海洋的惊叹 */
    background-image: linear-gradient(60deg, #3d3393 0%, #2b76b9 37%, #2cacd1 65%, #35eb93 100%);
}

.counter-container {
    /* 垂直居中 */
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin: 30px 50px;
}

/* 计数器 的内容由 js做出来*/
.counter {
    margin-top: 10px;
    font-size: 60px;
}

@media(max-width:580px) {
    /* 当页面宽度过低时, 子元素竖排显示 */
    body {
        flex-direction: column;
    }
}